Active sound cancellation control (active noise control, also referred to as “ANC”) is known as active noise cancellation against a rotation sound source caused by interference of rotor blades and rotor-stator blades. ANC can reduce noise by outputting from a control speaker a signal (control sound) having the same amplitude as, and having an opposite phase to, the noise.
For an active noise canceling technique, there is a technique of arranging, on a circumference, a plurality of control speakers around a rotation sound source. However, this technique requires many control speakers to simulate the rotation sound source. An object is to provide a rotor-stator blade interference noise reduction system in which the number of speakers can be reduced.